Casting apparatus



Filed Dec. 20, 1943 R. G. WILSON CASTING AP PARATUS 2 Shee'ts$heet l k W i\\\ V//// 4////V/ INVENTOR. I E0602 67/423022 BY Y lam 12M, Mann-1 (M ATTURNEYS R. G. WILSON 2,364,180

CASTING APPARATUS Filed Dec. 20. 1943 2 Sheets-Sheet 2 INVENTOR. Robe/Z 6'. fl zlson BY PM PM, Ila/1 FEM I ATTOFNTEYS Patented Dec. 5, 1944 bASTING APPARATUS; p 1 R rto. Wilson, Long B aenoaiir, l mnpplication December 2O,1943;;SerialNo;;514;885j

Thisvinvention relates to apparatus for casting diamond core bits and; has for its object the pro- :visioniof an improved apparatus ot this char- .acter; :The inventiontaims .to provide an improved. apparatus zof .theitypein whichth dia- 'monds. are lheldtin position in a mold'by means of a vacuum and in whichxthe metal to -form the :diamond co-re bit isipoured over the diamonds.

The l invention provides a casting apparatus comprising a carbon mold, preferably of graphite, having an annular channel forreceivingthe metal. and the diamonds, vacuum means -forsecuring the diamonds in position during casting, :an'interior member, preferably of #graphite, in

. engagement with the mold 'formingat least a partoflthe-inner wallof the moldand having an-upwardlyextending wall providing a chamber in whichx the metalzwis poured, together with meansto distribute the metal into the mold, and

means for securing-and adjusting a'blank bit rounding the interior member connects with the in position abovethe annular channel whereby the metal of the bit becomes attached'to the blankbit. .JIn an-advantageous embodiment of prevent small particles of metal being sucked port the collar (blank bit holder) in aligned spaced position above the annular channel of the mold. The blank bit holder comprises a blank bit and securing and adjusting means to align the blank bit in proper spaced relation with respect to the annular channel in the mold.

The interior member has upwardly extending side walls, preferably cylindrical, spaced inwardly from theblank bit to provide an annular space for a body of molten metal connecting with the metal in the annular channel which forms the bit. The chamber formed inside the upwardly extending side walls connects near the bottom with the annular space through a plurality of radially extending openings through which the metal poured into the chamber flows in all directions into the annular channel.

The bit holder and the bit are of cylindrical form having the same interior and exterior dif 2 Claims. (ergghl ameters andtherbodyof metal *in thes'pace-sur metal on the interior sideslofthe bit In order to'vefiect a suitable union or bondingof the 'bit to the bit holderpaplurality of spaced radial holes are formed in the bit holder near the lower extremity thereof and the metal flows into'the holes uniting the bit holder to-the bit.

These and other noverfeatures of the invention will be better understood after considering the "following discussion taken in conjunction with theaccompanying drawings, in which: f Fig. 1 is a. side. elevationahview, with parts in section; of apparatus embodying the invention; l

1 Fig. 2t 15' a plan view along the line2-'-2';of FiggLa'nd i i Fig. 3 isa plan view alongthe line 3-+3 of Fig. 1. j l i The apparatus illustrated in the drawings comprises a table or bench I of any suitable size and construction on which the apparatus for casting diamond core "bits "2 is mounted. The cup-shaped base member 3 is formed-of steel or iron and rests upon the table=and-' has an opening. in the bottom towhichjthe air pipe 4 is connectedasby threads. The air pipe is con nected to a vacuumpump #(not shown)" and is provided with" a quick action valve 5; vacuum relief valveili andavacuum gage1. 1 In order-:to

through the air pipe, I. preferablyconnect therein a filteri 8 which 'is filledwith any suitable small particles; such as l small stones, marbles or the like..l The base member has-an inward recess S in which the exterior cylindrical edge portion and, flat under surface of the graphite mold [0 rest, forming a close fitting joint. The depending cylindrical wall l2 has an annular channel l3 which defines thebottom and exterior cylindrical surface of the diamond core bit I4. The inner cylindrical face l5 of the depending wall l2 makes a close and sliding engagementwith an annular exterior recess in the lower part of the interior member I6. The lower exterior cylindrical wall I! of the interiormember forms the interior surface of the core bit. The mold has an annular recess l8 for receiving the cylindrical blank bit holder IS in proper alignment with respect to the annular channel l3. The blank bit 20 is threaded into the bit holder and there is suflicient play between the threads that the bit may be adjusted by means of the triangularly spaced adjustment screws 2|. By means of these screws and the seating of the bit holder the blank bit and the bit are contiguous.

The interior member l6 has an upwardly extending wall with a cylindrical exterior spaced inwardly a sufficient distance from the interior surface of the bit holder to provide a space 22 for receiving molten metal. The interior chamber 23 connects withthe space 22 at the bottom by means of a plurality of radially disposed holes 24. When molten metal is poured into the chamber 23, it flows radially in all directions through the holes 24 into the space 22 and then laterally into the annular channel below to form the bit.

While the mold and the interior member are advantageously formed of graphite or some other dense form of carbon they may be formed of refractory material. The form and arrangement of the interior member with respect to the mold and the blank bit makes it possible to obtain a relatively deep casting with a minimum of metal thereby increasing the density and uniformity ofthe metal'inthe bit and insuring a more uniform and positive engaging contact of the metal of the bit with the metal in the holes in the end of the bit ho1der.- v

The core bit and'attached bit holder are sevcred from the cylindrical body of metal between the interior member and the blank bit holder of the bit filling the space 22.

is poured quickly into the chamber 23 from which it spreads out and flows radially through the holes 24'into the annular channel l3. The metal is poured into the interior member until it rises, say, about three inches, above the top This creates a sufiicient pressure to form the desired dense casting and the reserve of heat in the mass of metal give the proper extent of draw to the metal of the bit during cooling.

I claim:

1. An improved apparatus for casting diamond core bits which comprises a mold, an interior member constructed and arranged to cooperate with the mold to form an annular channel in .,which is poured the metal to form the bit, means for positioning and securing a multiplicity of I diamonds in the annular channel during casting of the bit, a blank bit holder in concentrically.

a chamber for pouring metal into the interior member, an annular space between the interior member and the bit holder in communicating contact with the annular channel, and a pluby cutting out the interior on a lathe leaving the interior cylindrical surface of the blank bit holder co-extensive with the interior-cylindrical surface of the core bit.

I The depending wall [2 of the mold has a multiplicity of small holes 25 connecting the inside of the annular channel with the space 26 which may be placed under reduced pressure. One diamond 21 is held in position in each hole. As best shown in Fig. 3, the interior and exterior walls of the annular channel have ribs 28 and grooves 29 to form longitudinal grooves in the bit to facilitate the flow of water around the cutting face of the bit.

In forming a diamond core bit, the apparatus is assembled with the parts in the positions illustrated in the drawings and the valves 5 and 6 are manipulated to place the space 26 between thebase cup and the mold under any desired vacuum, say, from about two to twelve inches of 1 water. The diamonds are then set in the position shown, onediamond being spaced in each of the holes where it is held in position by the vacuum. The molten metal, usually an alloy steel,

rality of openings in the interior member connecting the chamber with the annular space.

' 2. An improved apparatus for casting diamond core bits which comprises a mold, an interior member constructed and arranged to cooperate with the mold to form an annular channel in ,precise position directly above the annular channel whereby the interior and exterior cylindrical vs-urfaces of the bit and bit holder are contiguous,

an annular space betweenl the insidev of the blank bit holder and the outsideof the interior member, a chamber in the interior of the in- .terior member, a plurality of holes connecting the chamber with the annular space, the annular spaceextending below the lower edge of the bit holder to enable the metal to flow radially from the annular space into the annular channel.

ROBERT G. WILSON. 

